Abstract

Room temperature and temperature dependent current-voltage characteristics of Schottky diodes fabricated on undoped GaN prepared with and without in situ nanonetwork by metal organic chemical vapor deposition have been studied. The features of the Schottky diodes depend strongly on the deposition conditions, namely, its thickness. Reduction in the point and line defect densities caused the Schottky barrier height to increase to for deposition time as compared to without nanonetwork. Similarly, the breakdown voltage also improved from for the reference to when nanonetwork was used. With optimized nanonetwork, full width at half maximum values of (0002) and x-ray rocking curves improved to 217 and , respectively, for a thick layer, as compared to 252 and for a reference sample of the same thickness, which are comparable to literature values. The photoluminescence linewidth also reduced to at with free excitons A and B clearly resolvable.

Received 20 July 2006Accepted 24 August 2006Published online 10 October 2006

Acknowledgments:

The work has been funded by a grant from the Air Force Office of Scientific Research (Kitt Reinhardt). The authors thank T. S. Kuan, W. J. Choyke, R. M. Feenstra, and R. Devaty for discussions and collaborations on the general topic of dislocation reduction in GaN.